1. Field of the Invention
The present invention relates to methods and systems of determining last hop device addresses.
2. Background Art
Last hop device discovery is an important capability in any agile network. Using the Cable Hybrid Fiber Coax (HFC) network as an example, client devices are commonly moved from one last hop device to another and roam from one network attachment point to another. With this agility, it becomes difficult for the network to know where the end client is attached to the network to support such things as QoS authorization and electronic surveillance. A method for discovering the last hop device works as follows:
1. The network element wishing to discover the last hop device does so by issuing an addressing packet with the destination address for the end client in question.
2. The last hope device intercepts the packet (based on some well understood criteria) and responds with its IP address related to the application in question (e.g. electronic surveillance).
3. Upon receipt of the response, the network element now knows the IP address of the last hop device and can address it directly.
The issue with this approach is the requirement to discover the last hop device every time it is desired to contact the last hop device for a given end client. This can be a burdensome in some environments where there is a repeated need to contact the last hop device, such as Voice over Internet Protocol (VoIP) applications where it may desired to perform QoS on the last hop device for each phone call routed therethrough (check line quality, connections, etc.)
One obvious solution to this problem is to cache or otherwise store the last hop device addresses in a database or other feature once they are know, i.e., after each client device has been sent the addressing packet. This process is still problematic as it still requires each client device to be sent the addressing packet, which is relatively inefficient.